The present disclosure relates to wireless communication devices, more particularly to optimizing over the air (OTA) performance of a wireless terminal.
Wireless terminal OTA performance requirements get tougher each year. Today, many companies are developing auto antenna tuners for the wireless industry. These tuners “map” the natural antenna impedance to another value that better suits the radio. This process is known as antenna matching.
The prior art methods for antenna matching focus on optimization of the transmission (TX) path performance. The TX mode antenna impedance is actively transformed back to the “ideal” 50 Ohm port impedance. The receiving (RX) mode performance is assumed to improve during optimization of the TX mode.
There are three main problems with the prior art approach. First, the TX system OTA performance, which is indicated by desired total radiated power (TRP), low battery current (Ibatt), and low operating phone temperature, may not optimize at 50 Ohms. Second, the RX system OTA performance, which is indicated by total isotropic sensitivity (TIS), may not achieve an optimum performance level with a TX mode derived antenna match. Given a typical antenna, the RX frequency band impedance is quite different when compared to the TX frequency band antenna impedance. Thus, there is no guarantee that the RX system will achieve optimum performance with a TX only derived auto-tuner match. Third, prior art tuning does not address the safety aspects associated with auto tuning methods. Safety issues include excessive generated heat (thermal issues), excessive battery current, and excessive output power (very high TRP).
Accordingly, a need exists for optimizing the RX mode OTA performance of a wireless terminal. A further need exists for simultaneously optimizing the TX mode OTA performance and the RX mode OTA performance of a wireless terminal. An additional need exists for controlling the maximum radiated power (TRP), the maximum phone temperature, and the maximum phone battery current (Ibatt).